Valves are commonly used to control the discharge of fluid from a pressure container or vessel. Typically, such valves include a handle or some other means by which a user can selectively control discharge of the container. Pressure containers may contain any number of products such as butane, propane, refrigerant gas, or any number of other types of industrial gases.
Due to governmental regulations in the United States, pressure containers containing refrigerants may only be filled once. Thus, such pressure containers can be initially charged or filled with the refrigerant; however, once the refrigerant has been discharged from the container, the container may not be refilled again.
There are a number of prior art valves which exist not only for use with non-refillable containers, but also refillable containers. One group of patents representative of valves which are used in conjunction with non-refillable containers include patents assigned to Amtrol, Inc., of West Warwick, R.I. One specific example includes the U.S. Pat. No. 4,813,375. This reference discloses a non-refillable valve including a housing with a central bore, and three distinct portions within the central bore of particular diameters. The lower portion of the central bore is narrower than a middle portion which in turn is narrower than an upper portion. The lower end of the valve housing sealingly engages the pressure container. A valve stem is rotatably positioned in the upper portion of the central bore. The valve stem itself includes a vertical bore formed in its bottom portion. A resilient valve sealing member is slidably received in the bore of the valve stem. When the pressure container is filled, a top rim portion of the sealing member is pressingly positioned in the upper portion of the central bore. After filling, the valve sealing member is pushed downward into the middle portion which allows the valve to contact a seating surface thus sealing the pressure container. A non-compressed top rim of the sealing member is wider than the upper portion of the central bore, which prevents the sealing member from moving back up into the upper portion of the central bore. If an attempt is made to refill the container, the sealing member engages the seating surface thus preventing refill. Additional U.S. patents disclosing similar valves include the U.S. Pat. Nos. 5,295,502; 4,573,611; and 5,036,876.
While the foregoing references may be adequate for their intended purposes, there is still a need for a valve of simple and reliable construction which prevents refilling of a pressure container.